Probably ... between the standard deduction for HOH + 2 kids under the age of 17 then you will not owe much at all if any so the withholding reflects that. On the W-4 you filled out if you clicked on HOH and then entered 2 kids as qualifying children then the employer withholds based on this information ... the new W-4 system is aimed at keeping your refund as close to zero as possible. If you want to pump the refund then switch to SINGLE and remove one or both of the kids then you will have more withheld naturally and less in your paycheck.
Use the Tax Withholding Estimator on the IRS web site to figure out what you (and your spouse if married) should each put on the W-4 forms that you give to your employers. It's much easier than using the worksheets on the form. It will let you adjust your withholding to get the approximate refund amount that you want.
Tax Withholding Estimator
